I'm trying to get a better handle on my workout routine. Right now I do upper body one day, and legs the next day. I workout 5 days a week. I do aerobics daily. How often do I change up the routine? I've heard that at my age (59) rest days are more important; true or false? I feel fine with my current routine, with plenty of energy etc. I have been adding new exercises a little at a time. I'm just not sure how to structure my workouts for maximum effectiveness.